Akt Inhibitor Advancements: From Capivasertib Approval to Covalent-Allosteric Promises.

Akt kinase is vital in cell growth, survival, metabolism, and migration. Dysregulation of Akt signaling is implicated in cancer and metabolic disorders. In the context of cancer, overactive Akt promotes cell survival and proliferation. This has spurred extensive research into developing Akt inhibitors as potential therapeutic agents to disrupt aberrant Akt signaling. Akt inhibitors are classified into three main types: ATP-competitive, allosteric, and covalent-allosteric inhibitors (CAAIs). ATP-competitive inhibitors compete with ATP for binding to Akt, allosteric inhibitors interact with the Pleckstrin homology (PH) domain, and covalent-allosteric inhibitors form covalent bonds, making them more potent and selective. Notably, capivasertib (AZD5363), a potent ATP-competitive Akt inhibitor, received FDA approval in November 2023 for use in combination with the estrogen receptor degrader fulvestrant to treat breast cancer. Challenges remain, including improving selectivity, identifying biomarkers to tailor treatments, and enhancing therapeutic efficacy while minimizing adverse effects. Particularly covalent-allosteric inhibitors hold promise for future more effective and personalized treatments.

Circadian organization of lipid landscape is perturbed in type 2 diabetic patients.

Lipid homeostasis in humans follows a diurnal pattern in muscle and pancreatic islets, altered upon metabolic dysregulation. We employ tandem and liquid-chromatography mass spectrometry to investigate daily regulation of lipid metabolism in subcutaneous white adipose tissue (SAT) and serum of type 2 diabetic (T2D) and non-diabetic (ND) human volunteers (n = 12). Around 8% of ≈440 lipid metabolites exhibit diurnal rhythmicity in serum and SAT from ND and T2D subjects. The spectrum of rhythmic lipids differs between ND and T2D individuals, with the most substantial changes observed early morning, as confirmed by lipidomics in an independent cohort of ND and T2D subjects (n = 32) conducted at a single morning time point. Strikingly, metabolites identified as daily rhythmic in both serum and SAT from T2D subjects exhibit phase differences. Our study reveals massive temporal and tissue-specific alterations of human lipid homeostasis in T2D, providing essential clues for the development of lipid biomarkers in a temporal manner.

Inactivation mechanisms of influenza A virus under pH conditions encountered in aerosol particles as revealed by whole-virus HDX-MS.

Multiple respiratory viruses, including influenza A virus (IAV), can be transmitted via expiratory aerosol particles, and aerosol pH was recently identified as a major factor influencing airborne virus infectivity. Indoors, small exhaled aerosols undergo rapid acidification to pH ~4. IAV is known to be sensitive to mildly acidic conditions encountered within host endosomes; however, it is unknown whether the same mechanisms could mediate viral inactivation within the more acidic aerosol micro-environment. Here, we identified that transient exposure to pH 4 caused IAV inactivation by a two-stage process, with an initial sharp decline in infectious titers mainly attributed to premature attainment of the post-fusion conformation of viral protein haemagglutinin (HA). Protein changes were observed by hydrogen-deuterium exchange coupled to mass spectrometry (HDX-MS) as early as 10 s post-exposure to acidic conditions. Our HDX-MS data are in agreement with other more labor-intensive structural analysis techniques, such as X-ray crystallography, highlighting the ease and usefulness of whole-virus HDX-MS for multiplexed protein analyses, even within enveloped viruses such as IAV. Additionally, virion integrity was partially but irreversibly affected by acidic conditions, with a progressive unfolding of the internal matrix protein 1 (M1) that aligned with a more gradual decline in viral infectivity with time. In contrast, no acid-mediated changes to the genome or lipid envelope were detected. Improved understanding of respiratory virus fate within exhaled aerosols constitutes a global public health priority, and information gained here could aid the development of novel strategies to control the airborne persistence of seasonal and/or pandemic influenza in the future. IMPORTANCE It is well established that COVID-19, influenza, and many other respiratory diseases can be transmitted by the inhalation of aerosolized viruses. Many studies have shown that the survival time of these airborne viruses is limited, but it remains an open question as to what drives their infectivity loss. Here, we address this question for influenza A virus by investigating structural protein changes incurred by the virus under conditions relevant to respiratory aerosol particles. From prior work, we know that expelled aerosols can become highly acidic due to equilibration with indoor room air, and our results indicate that two viral proteins are affected by these acidic conditions at multiple sites, leading to virus inactivation. Our findings suggest that the development of air treatments to quicken the speed of aerosol acidification would be a major strategy to control infectious bioburdens in the air.

ER-Golgi-localized proteins TMED2 and TMED10 control the formation of plasma membrane lipid nanodomains.

To promote infections, pathogens exploit host cell machineries such as structural elements of the plasma membrane. Studying these interactions and identifying molecular players are ideal for gaining insights into the fundamental biology of the host cell. Here, we used the anthrax toxin to screen a library of 1,500 regulatory, cell-surface, and membrane trafficking genes for their involvement in the intoxication process. We found that endoplasmic reticulum (ER)-Golgi-localized proteins TMED2 and TMED10 are required for toxin oligomerization at the plasma membrane of human cells, an essential step dependent on localization to cholesterol-rich lipid nanodomains. Biochemical, morphological, and mechanistic analyses showed that TMED2 and TMED10 are essential components of a supercomplex that operates the exchange of both cholesterol and ceramides at ER-Golgi membrane contact sites. Overall, this study of anthrax intoxication led to the discovery that lipid compositional remodeling at ER-Golgi interfaces fully controls the formation of functional membrane nanodomains at the cell surface.

Pancytopenia in a Case of Aplastic Anaemia/Paroxysmal Nocturnal Haemoglobinuria Unmasked by SARS-CoV-2 Infection: A Case Report.

During an acute SARS-CoV-2 infection, a diagnosis of Aplastic Anaemia associated with Paroxysmal Nocturnal Haemoglobinuria (AA/PNH) was made in a 78-year-old woman who had presented to the emergency department with severe pancytopenia. It is possible that she had subclinical AA/PNH that was unmasked during the acute COVID-19 infection, but we can also suspect a direct role of the virus in the pathogenesis of the disease, or we can hypothesize that COVID-19 infection changed the phosphatidylinositol glycan class A (PIGA) gene pathway.

Essential oil of Foeniculum vulgare subsp. piperitum fruits exerts an anti­tumor effect in triple­negative breast cancer cells.

At present, the growing spread of tumor cases worldwide renders the research of new promising and selective anticancer drugs urgent. The biological action of extracts of medicinal plants or their essential oils (EOs) is an emerging field of interest, since they could comprise a rich source of phytochemicals that can prove promising. In the present study, the biological activity and mechanism of action of the EO of Foeniculum vulgare subsp. piperitum fruits (FVPEO) were investigated using MTT assays, morphological analyses and western blotting in MDA­MB231 cells, a triple­negative breast cancer cell line. The findings revealed that FVPEO could exert strong anticancer effects, causing a dose­dependent inhibition of breast cancer MDA­MB231 cell growth, accompanied with DNA condensation and fragmentation. The cytotoxic effect of FVPEO was counteracted by the addition of the antioxidant N­acetylcysteine and was associated with a marked increase in reactive oxygen species and stress­related proteins; such as manganese superoxide dismutase, c­Jun, phospho­c­Jun N­terminal kinase and nuclear factor E2­related factor 2, and the latter's transcriptional targets, Heme oxygenase­1 and NAD(P)H quinone oxidoreductase 1 (NQO1). As evidenced by the activation of caspase­3 and fragmentation of poly(ADP­ribose) polymerase­1, which are typical apoptosis markers, FVPEO promoted apoptotic cell death accompanied with an increase in phosphorylated H2A histone family member X and the activation of the NQO1/p53 axis. In combination, the present experiments provided evidence that FVPEO could represent a reservoir of biologically active compounds suitable for both cancer prevention and treatment.

Sphingolipids control dermal fibroblast heterogeneity.

Human cells produce thousands of lipids that change during cell differentiation and can vary across individual cells of the same type. However, we are only starting to characterize the function of these cell-to-cell differences in lipid composition. Here, we measured the lipidomes and transcriptomes of individual human dermal fibroblasts by coupling high-resolution mass spectrometry imaging with single-cell transcriptomics. We found that the cell-to-cell variations of specific lipid metabolic pathways contribute to the establishment of cell states involved in the organization of skin architecture. Sphingolipid composition is shown to define fibroblast subpopulations, with sphingolipid metabolic rewiring driving cell-state transitions. Therefore, cell-to-cell lipid heterogeneity affects the determination of cell states, adding a new regulatory component to the self-organization of multicellular systems.

S-acylation controls SARS-CoV-2 membrane lipid organization and enhances infectivity.

SARS-CoV-2 virions are surrounded by a lipid bilayer that contains membrane proteins such as spike, responsible for target-cell binding and virus fusion. We found that during SARS-CoV-2 infection, spike becomes lipid modified, through the sequential action of the S-acyltransferases ZDHHC20 and 9. Particularly striking is the rapid acylation of spike on 10 cytosolic cysteines within the ER and Golgi. Using a combination of computational, lipidomics, and biochemical approaches, we show that this massive lipidation controls spike biogenesis and degradation, and drives the formation of localized ordered cholesterol and sphingolipid-rich lipid nanodomains in the early Golgi, where viral budding occurs. Finally, S-acylation of spike allows the formation of viruses with enhanced fusion capacity. Our study points toward S-acylating enzymes and lipid biosynthesis enzymes as novel therapeutic anti-viral targets.

GRASP55 regulates intra-Golgi localization of glycosylation enzymes to control glycosphingolipid biosynthesis.

The Golgi apparatus, the main glycosylation station of the cell, consists of a stack of discontinuous cisternae. Glycosylation enzymes are usually concentrated in one or two specific cisternae along the cis-trans axis of the organelle. How such compartmentalized localization of enzymes is achieved and how it contributes to glycosylation are not clear. Here, we show that the Golgi matrix protein GRASP55 directs the compartmentalized localization of key enzymes involved in glycosphingolipid (GSL) biosynthesis. GRASP55 binds to these enzymes and prevents their entry into COPI-based retrograde transport vesicles, thus concentrating them in the trans-Golgi. In genome-edited cells lacking GRASP55, or in cells expressing mutant enzymes without GRASP55 binding sites, these enzymes relocate to the cis-Golgi, which affects glycosphingolipid biosynthesis by changing flux across metabolic branch points. These findings reveal a mechanism by which a matrix protein regulates polarized localization of glycosylation enzymes in the Golgi and controls competition in glycan biosynthesis.

New-Onset Cancer in the HF Population: Epidemiology, Pathophysiology, and Clinical Management.

PURPOSE OF REVIEW: Oncological treatments are known to induce cardiac toxicity, but the impact of new-onset cancer in patients with pre-existing HF remains unknown. This review focuses on the epidemiology, pathophysiological mechanisms, and clinical implications of HF patients who develop malignancies. RECENT FINDINGS: Novel findings suggest that HF and cancer, beside common risk factors, are deeply linked by shared pathophysiological mechanisms. In particular, HF itself may enhance carcinogenesis by producing pro-inflammatory cytokines, and it has been suggested that neurohormonal activation, commonly associated with the failing heart, might play a pivotal role in promoting neoplastic transformation. The risk of malignancies seems to be higher in HF patients compared to the general population, probably due to shared risk factors and common pathophysiological pathways. Additionally, management of these patients represents a challenge for clinicians, considering that the co-existence of these diseases significantly worsens patients' prognosis and negatively affects therapeutic options for both diseases.

Golgi maturation-dependent glycoenzyme recycling controls glycosphingolipid biosynthesis and cell growth via GOLPH3.

Glycosphingolipids are important components of the plasma membrane where they modulate the activities of membrane proteins including signalling receptors. Glycosphingolipid synthesis relies on competing reactions catalysed by Golgi-resident enzymes during the passage of substrates through the Golgi cisternae. The glycosphingolipid metabolic output is determined by the position and levels of the enzymes within the Golgi stack, but the mechanisms that coordinate the intra-Golgi localisation of the enzymes are poorly understood. Here, we show that a group of sequentially-acting enzymes operating at the branchpoint among glycosphingolipid synthetic pathways binds the Golgi-localised oncoprotein GOLPH3. GOLPH3 sorts these enzymes into vesicles for intra-Golgi retro-transport, acting as a component of the cisternal maturation mechanism. Through these effects, GOLPH3 controls the sub-Golgi localisation and the lysosomal degradation rate of specific enzymes. Increased GOLPH3 levels, as those observed in tumours, alter glycosphingolipid synthesis and plasma membrane composition thereby promoting mitogenic signalling and cell proliferation. These data have medical implications as they outline a novel oncogenic mechanism of action for GOLPH3 based on glycosphingolipid metabolism.

Genetic characterization of ABT-199 sensitivity in human AML.

Acute myeloid leukemias (AML) with mutations in the NPM1 gene (NPM1c+) represent a large AML subgroup with varying response to conventional treatment, highlighting the need to develop targeted therapeutic strategies for this disease. We screened a library of clinical drugs on a cohort of primary human AML specimens and identified the BCL2 inhibitor ABT-199 as a selective agent against NPM1c+ AML. Mutational analysis of ABT-199-sensitive and -resistant specimens identified mutations in NPM1, RAD21, and IDH1/IDH2 as predictors of ABT-199 sensitivity. Comparative transcriptome analysis further uncovered BCL2A1 as a potential mediator of ABT-199 resistance in AML. In line with our observation that RAD21 mutation confers sensitivity to ABT-199, we provide functional evidence that reducing RAD21 levels can sensitize AML cells to BCL2 inhibition. Moreover, we demonstrate that ABT-199 is able to produce selective anti-AML activity in vivo toward AML with mutations associated with compound sensitivity in PDX models. Overall, this study delineates the contribution of several genetic events to the response to ABT-199 and provides a rationale for the development of targeted therapies for NPM1c+ AML.

Meeting Report - The 2019 FEBS special meeting on sphingolipid biology: sphingolipids in physiology and pathology.

Sphingolipids are a fundamental class of molecules that are involved in structural, organizational and signaling properties of eukaryotic membranes. Defects in their production or disposal lead to acquired and inherited human diseases. A growing community of scientists has embraced the challenge to dissect different aspects of sphingolipid biology using a variety of approaches, and a substantial part of this community met last May in the beautiful town of Cascais in Portugal. Over 200 scientists from 26 countries animated the conference, held in a 15th century citadel, sharing their data and opinions on the current understanding and future challenges in sphingolipid research. Here, we report some of their contributions to provide the readers with a bird's-eye view of the themes discussed at the meeting.

Positive selection in Europeans and East-Asians at the ABCA12 gene.

Natural selection acts on genetic variants by increasing the frequency of alleles responsible for a cellular function that is favorable in a certain environment. In a previous genome-wide scan for positive selection in contemporary humans, we identified a signal of positive selection in European and Asians at the genetic variant rs10180970. The variant is located in the second intron of the ABCA12 gene, which is implicated in the lipid barrier formation and down-regulated by UVB radiation. We studied the signal of selection in the genomic region surrounding rs10180970 in a larger dataset that includes DNA sequences from ancient samples. We also investigated the functional consequences of gene expression of the alleles of rs10180970 and another genetic variant in its proximity in healthy volunteers exposed to similar UV radiation. We confirmed the selection signal and refine its location that extends over 35 kb and includes the first intron, the first two exons and the transcription starting site of ABCA12. We found no obvious effect of rs10180970 alleles on ABCA12 gene expression. We reconstructed the trajectory of the T allele over the last 80,000 years to discover that it was specific to H. sapiens and present in non-Africans 45,000 years ago.

Ultra-Low-Level Laser Therapy and Acupuncture Libralux: What Is so Special?

BACKGROUND: Contrary to the most credited theories on laser therapy that see power/energy as the major factors to its effectiveness, a technique using an extremely low power/energy laser stimulation to treat musculoskeletal pain and dysfunction is proposed. The stimulus consists of a 20 s train of modulated pulses with an average power below 0.02 mW and is applied on sequences of acupuncture points selected according to the impaired segment of the patient's body. Methods: Modifications on the extracellular soft tissue matrix and on the "fascia" were sonographically demonstrated. Laboratory and clinical tests confirmed the effectiveness. Results: Responses similar to those experienced in acupuncture were observed. The device-a CE Class IIa certified medical device named Libralux-affords a clinically proven effectiveness exceeding 80% in the treatment of musculoskeletal conditions and associated motor dysfunctions. An average of just three application sessions was generally sufficient to overcome the dysfunction. Conclusions: The development of the method is supported by over 20 years of R&D activities, with a range of experiments discussed in several papers published in indexed peer-reviewed journals. A few considerations regarding the possible physiological action mechanisms involved are proposed in this paper.

Imaging Lipid Metabolism at the Golgi Complex.

The development of fluorescence-based molecular imaging has revolutionized cell biology allowing the visualization of specific biomolecules at the microscopic and, more recently, at the nanoscopic scale while in their relevant biological contexts. Nonetheless, despite the imaging toolkit for biologists interested in exploring the subcellular localization and dynamics of proteins and nucleic acids has expanded exponentially in the last decades, the means to visualize and track lipids in cells did not develop to the same extent until recently. Here we described some basic fluorescence-based techniques that can be used in standard cell biology laboratories to visualize subcellular pools of specific lipids and to evaluate their regional metabolism. Specifically, here we focus on the imaging-based analysis of phosphoinositide and sphingolipid metabolism at the Golgi complex.

Visualizing sphingolipid biosynthesis in cells.

Biosynthetic pathways play a fundamental role in the building and operation of the cell by synthesizing the constituents by which the cell is constructed, and by producing signalling intermediates that play a key role in cell regulation. While a lot is known about the metabolite profile of the cells and about the biochemical pathways through which these metabolites are produced, the cellular localization of the biosynthetic machineries and the importance of this localization to the regulation of the metabolism has often been given less attention. This derives from the fact that, for several of these pathways, the enzymes involved are found colocalized in one compartment where their specific localization is unlikely to influence their function. The sphingolipid (SL) metabolic pathway is a notable exception to this as SL synthetic enzymes are laid out on a specific pattern across the secretory compartments. Such compartmentalized organization of the SL synthesis has functional implications as it makes the fine-tuned regulation of the process possible by allowing cells to regulate specific segments of the pathway in response to stimuli and for adaptation. The organization, dynamics, and regulation of the SLs and their biosynthetic machinery have been investigated using imaging-based methods. Here we provide a brief introduction to the techniques that have been or that could be employed to visualize the SL biosynthetic machinery and SLs themselves and discuss the insights provided by these studies in understanding this metabolism.